toxcore/toxcore/mono_time.c
iphydf 6872c14e1a
Avoid use of global mutable state in mono_time on win32.
This uses a trick to get read-write access to `this` from a `const`
member function, similar to C++ `mutable`, but uglier.
2018-09-03 20:03:47 +00:00

139 lines
3.6 KiB
C

#ifndef _XOPEN_SOURCE
#define _XOPEN_SOURCE 600
#endif
#if !defined(OS_WIN32) && (defined(_WIN32) || defined(__WIN32__) || defined(WIN32))
#define OS_WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif
#ifdef __APPLE__
#include <mach/clock.h>
#include <mach/mach.h>
#endif
#ifndef OS_WIN32
#include <sys/time.h>
#endif
#include "mono_time.h"
#include <stdlib.h>
#include <time.h>
#include "ccompat.h"
/* don't call into system billions of times for no reason */
struct Mono_Time {
uint64_t time;
uint64_t base_time;
#ifdef OS_WIN32
uint64_t last_clock_mono;
uint64_t add_clock_mono;
#endif
mono_time_current_time_cb *current_time_callback;
void *user_data;
};
static uint64_t current_time_monotonic_default(Mono_Time *mono_time, void *user_data)
{
uint64_t time;
#ifdef OS_WIN32
uint64_t old_add_clock_mono = mono_time->add_clock_mono;
time = (uint64_t)GetTickCount() + mono_time->add_clock_mono;
/* Check if time has decreased because of 32 bit wrap from GetTickCount(), while avoiding false positives from race
* conditions when multiple threads call this function at once */
if (time + 0x10000 < mono_time->last_clock_mono) {
uint32_t add = ~0;
/* use old_add_clock_mono rather than simply incrementing add_clock_mono, to handle the case that many threads
* simultaneously detect an overflow */
mono_time->add_clock_mono = old_add_clock_mono + add;
time += add;
}
mono_time->last_clock_mono = time;
#else
struct timespec clock_mono;
#if defined(__APPLE__)
clock_serv_t muhclock;
mach_timespec_t machtime;
host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &muhclock);
clock_get_time(muhclock, &machtime);
mach_port_deallocate(mach_task_self(), muhclock);
clock_mono.tv_sec = machtime.tv_sec;
clock_mono.tv_nsec = machtime.tv_nsec;
#else
clock_gettime(CLOCK_MONOTONIC, &clock_mono);
#endif
time = 1000ULL * clock_mono.tv_sec + (clock_mono.tv_nsec / 1000000ULL);
#endif
return time;
}
Mono_Time *mono_time_new(void)
{
Mono_Time *mono_time = (Mono_Time *)malloc(sizeof(Mono_Time));
if (mono_time == nullptr) {
return nullptr;
}
mono_time->current_time_callback = current_time_monotonic_default;
mono_time->user_data = nullptr;
#ifdef OS_WIN32
mono_time->last_clock_mono = 0;
mono_time->add_clock_mono = 0;
#endif
mono_time->time = 0;
mono_time->base_time = (uint64_t)time(nullptr) - (current_time_monotonic(mono_time) / 1000ULL);
mono_time_update(mono_time);
return mono_time;
}
void mono_time_free(Mono_Time *mono_time)
{
free(mono_time);
}
void mono_time_update(Mono_Time *mono_time)
{
mono_time->time = (current_time_monotonic(mono_time) / 1000ULL) + mono_time->base_time;
}
uint64_t mono_time_get(const Mono_Time *mono_time)
{
return mono_time->time;
}
bool mono_time_is_timeout(const Mono_Time *mono_time, uint64_t timestamp, uint64_t timeout)
{
return timestamp + timeout <= mono_time_get(mono_time);
}
void mono_time_set_current_time_callback(Mono_Time *mono_time,
mono_time_current_time_cb *current_time_callback, void *user_data)
{
if (current_time_callback == nullptr) {
mono_time->current_time_callback = current_time_monotonic_default;
mono_time->user_data = nullptr;
} else {
mono_time->current_time_callback = current_time_callback;
mono_time->user_data = user_data;
}
}
/* return current monotonic time in milliseconds (ms). */
uint64_t current_time_monotonic(Mono_Time *mono_time)
{
return mono_time->current_time_callback(mono_time, mono_time->user_data);
}